As the design of vehicles and automobiles has evolved, headlights have continually been reconfigured to improve the aerodynamics of the front end of the vehicle. Modern headlights are designed so that their lenses follow the contour of the vehicle to provide an aerodynamically efficient exterior surface. However, adjustment of these headlights must still be performed in order to provide an optimal beam of light and to prevent the aiming of light beams toward oncoming vehicles. Automotive manufacturers' demand for aerodynamically efficient headlight designs has led to modular designs requiring the headlight adjustment mechanism be located within the engine compartment so that the adjustment can be easily performed without removing any exterior trim pieces. Thus, the constraints of the installation area and the demands of the automobile manufacturers for aerodynamic headlight designs make it desirable to provide an adjuster for use with the aerodynamic designs that is adjustable from inside the engine compartment using ordinary tools, and translates rotational motion of the adjusting part into adjustment of the reflector within the headlight assembly. There are a wide variety of prior art adjuster devices including, among others, the devices disclosed in U.S. Pat. Nos. 5,707,133 and 5,214,971 to Burton, the inventor of the present invention, the disclosures of which are incorporated herein by reference.
Automotive lamp assemblies used as headlights typically comprise several basic parts: a support frame, a reflector, a lens, a bulb, and one or more adjusters. The support frame usually houses the reflector and the bulb on a pivotable mounting to allow the aim of the light to be adjusted using the adjuster. The lens seals the front of the assembly to protect it from the elements assailing the front end of the vehicle and provides an aerodynamic shape and attractive appearance. Traditionally, fixed and movable ball joints have engaged the headlamp reflector. Actuating the moveable ball joint results in altering the angle of the headlamp reflector by pivoting the reflector about the fixed ball joints. In certain variations, two movable ball joints are used to enable vertical and horizontal aiming of the headlamp.
In some instances, an aiming screw or gear screw replaces the moveable ball joint. With the screw assembly, the reflector mounts inside the housing on a gear screw assembly and is adjustable horizontally and/or vertically using adjusters that interface with the reflector by moving the gear screw. One such assembly is disclosed in U.S. Pat. No. 7,052,164 to Burton, which is incorporated herein by reference. A self-locking nut or grommet can also be incorporated into a gear screw adjuster to provide movability in both horizontal and vertical directions. A self-locking nut providing such movement is disclosed in U.S. Pat. No. 4,503,486 to Makita. As shown in FIG. 3 of the Makita patent, the self-locking nut is freely rockable in the direction shown by the arrow P3 for the horizontal adjustment of the optical axis. However, the adjuster of Makita requires multiple steps for assembly into the headlamp housing, where the self-locking nut must be mounted to the reflector bracket and the adjusting rod then threaded into the nut.
Accordingly, the need exists for a compact gear screw adjuster assembly that can be securely retained in a wall or other structure of the headlamp housing, allows for easy installation and adjustment of the headlamp in multiple directions through use of a multi-function grommet, reduces the sealing problems associated with facially sealing O-rings, provides a clutching feature to prevent system damage due to over-travel, and is more efficient and cost effective to manufacture and to assemble to the headlamp housing.